Sen. Joe Biden of Delaware set the stage for Sen. Barack Obama’s historic address as the Democratic presidential nominee by launching a heated attack Wednesday night tying Sen. John McCain to the Bush White House and telling voters they had the power to change the country’s direction.

“At the start of this campaign, we had a very simple idea: Change does not start from the top down. It starts from the bottom up,” Obama said, looking forward to his own acceptance speech Thursday night before as many as 75,000 people at Invesco Field in Denver.

Biden took the stage to reinforce that message, working to reassure working-class voters that Obama, a Harvard-educated lawyer, was not the out-of-touch elitist his Republican opponents were making him out to be.

“I watched how he touched people, how he inspired them, and I realized he has tapped into the oldest American belief of all: We don’t have to accept a situation we cannot bear,” said Biden, who ended his own presidential campaign early in the nominating process. “We have the power to change it.”

Biden reaches out to Clinton backers
Biden also reached out to supporters of Obama’s vanquished rival, Sen. Hillary Rodham Clinton of New York, saying how “moved” he was watching Clinton address the convention Tuesday night.

And while he warmly called McCain “my friend of 30 years,” he showed no reluctance to link McCain to President Bush and Vice President Dick Cheney.

“Our country is less secure and more isolated than at any time in recent history,” Biden said. “The Bush-McCain foreign policy has dug us into a very deep hole, with very few friends to help us climb out. ...

“John McCain was wrong,” Biden added. “Barack Obama was right.”

On a host of issues, from the war to oil company profits to the minimum wage, Biden led the delegates in a chant: “That’s not change. That’s more of the same.”

The McCain campaign immediately fired back, issuing a statement that read in part:

“We need a leader who understands that you don’t vote against funding for troops in harm’s way. We need a leader who supports victory in Iraq, and doesn't try to legislate failure.”

Recalling criticisms Biden made during the primary campaign, the statement added: “Americans have seen with their own eyes what Joe Biden has repeatedly made clear — Barack Obama does not have the judgment or experience to be president of the United States.”

Clinton goes to bat for Obama
Biden is known as one of the party’s most dynamic speakers, but even he had a tough job taking the podium after a vintage performance from former President Bill Clinton, who laid to rest any speculation that he would not enthusiastically back Obama.

“I am here first to support Barack Obama,”
Clinton said
, opening his address in characteristic fashion by deviating from the prepared text aides distributed to reporters ahead of time. “... Barack Obama is ready to lead America and restore American leadership in the world.”

Clinton’s speech had been as hotly anticipated as Biden’s. His support for Obama had seemed tepid at best coming in, but Clinton made it clear that he was now behind the nominee, declaring, “Barack Obama is the man for this job.”

Kerry wins over crowd
Whipped to a frenzy by Clinton’s performance, the delegates gave a muted reception to the Democrats’ 2004 nominee, Sen. John Kerry of Massachusetts. The reaction was tepid even when Kerry got off his best applause line, claiming that McCain had sided with President Bush 90 percent of the time and adding: “90 percent of George Bush is just more than we can take.”

But Kerry soldiered on, slowly winning the crowd over with a strong denunciation of the CIA’s interrogation of prisoners of war at Guantanamo Bay, Cuba.

Reciting what he said were McCain’s changes of position since running for president, Kerry brought the crowd to its feet by declaring: “Are you kidding? ... Before debating Barack Obama, John McCain should finish the debate with himself.”

“The Bush-McCain Republicans have been wrong again and again and again,” he added.

Obama readies for his big night
Obama, meanwhile, was putting the final touches on the acceptance speech he will deliver Thursday night in an outdoor arena, recalling John F. Kennedy’s address in Los Angeles in 1960.

Obama’s chief strategist, David Axelrod, said Obama was still refining his speech, which he was writing himself. The speech will make a “clear and direct” case about the risks of choosing McCain , whom Obama will “not shy away from attacking,” Axelrod said.